Respiratory viral infections, particularly by human rhinoviruses, play important roles in inception, exacerbation and chronicity of asthma. The goal of this AADRC is to determine the mechanisms by which respiratory viruses contribute to the pathogenesis of asthma. The Virology Core is established to provide uniform stocks of respiratory viruses and related materials for each of the five projects and quantify (by infectivity assay and qPCR) viral material produced in those projects. To accomplish this goal, standardized stocks of human rhinovirus (HRV) strains will be prepared for Projects by Gern, Bertics, Huttenlocher, Rosenthal, and Palmenberg. For Project by Gern, the Core will provide the safety-tested human HRV16 for inoculation of selected study subjects and quantify the amount of HRV16 in the airways of inoculated subjects by quantitative real-time PCR (qPCR). In addition, we will identify sero-negative subjects for Project by Gern by testing serum specimens from prospective subjects for antibodies to HRV16. Project by Bertics is designed to determine the signal transduction pathways of human monocytes/macrophages following activation by HRVs. Project by Huttenlocher will characterize how HRV infections modulate the adhesion and migration of neutrophils. The Core will produce fully infectious HRV16 and inactivated derivatives for these two projects. In addition, we will help to determine the binding of HRV16 to macrophages and neutrophils. Project by Rosenthal is to develop a murine model of picornavirus infection and to study mechanisms of airway inflammation with this model; the Core will provide Mengo virus for this project and quantify the viral material produced in this project. Finally, project by Palmenberg will examine the role of host shutoff activities by HRV infections in the pathogenesis of HRV-induced asthma exacerbations. The core will provide stocks of 101 HRV serotypes and quantify the viral material produced in this project.